• 发布者：LEI BI RESEARCH GROUP 发布时间：2020-07-29 13:56:05 分享到：

      On the afternoon of November 25, 2024, the Engineering Research Center hosted the 30th ERC Scholars Forum in Meeting Room 402 of Research Building No. 5. The event featured Professor V.I. Belotelov from the Department of Physics at Lomonosov Moscow State University as the keynote speaker, who delivered an insightful academic presentation on "Opto-Magnetic Effects in All-Dielectric Magnetic Nanostructures" for faculty and students.

      All-dielectric nanostructures show significant promise for effective spin control in magnetic materials using femtosecond laser pulses. By carefully tuning specific parameters, these structures can induce various optical resonances (including waveguide modes, Mie resonances, and Fabry-Pérot resonances) in magnetic systems. This enables precise distribution of optical spin angular momentum within the magnetic material through effective magnetic fields generated by the inverse magneto-optical Faraday effect and Cotton-Mouton effect, ultimately exciting diverse high-amplitude spin-wave modes.

      Notably, in magneto-photonic crystals and nanostructured magnetic thin films, spin waves can be excited as standing waves localized in one-dimensional or three-dimensional configurations. Particularly, when optical resonances are induced within magnetic nanospheres or nanocylinders, the inverse Faraday effect's effective field demonstrates both localized and non-uniform reconstruction across extended spatial domains. This enables the excitation of higher-order standing wave modes with exceptional spatial control.

      On the other hand, when non-magnetic nanolattices are deposited on magnetic thin films, femtosecond laser pulses can excite ultrashort spin waves with wavelengths of approximately 100-300 nm — significantly shorter than the optical wavelength in the magnetic medium. In this configuration, the nanolattices perform a dual function: they not only enable the generation of these subwavelength spin waves but also facilitate their direct observation, a capability unattainable in homogeneous magnetic films.

      Furthermore, this nanolattice architecture gives rise to novel opto-magnetic phenomena, such as the inverse transverse Kerr effect, which substantially expands the operational spectrum for optical spin control.

    The seminar fostered vibrant academic exchanges, with Professor V.I. Belotelov engaging in profound discussions with faculty and students. The dialogue focused on cutting-edge topics including light-spin interactions and multidimensional standing spin wave generation at micro/nano scales. Through this dynamic exchange, participants not only expanded their scientific horizons but also gained deeper mechanistic insights into opto-magnetic phenomena in dielectric-magnetic hybrid systems.